Functionalized Polymers and Regenerative Agents

Objectives

We focus on the development of new polymers based on biomacromolecules as well as on chemical polymerization. In doing so we optimize the polymer phase with respect to polymer size and degree of cross linking and affect the polymer properties (solubility, degradability). Also we develop facile chemical functionalization methods for modifying existing polymers with respect immunological properties and create anchor groups for attaching (bio)molecules with e.g. cell adhesion properties. In addition our group provides small molecular drugs used within the rebirth consortium.

Major projects:

a) Polysaccharide-based hydrogels based on functionalized building blocks – a versatile toolbox for tissue engineering

We developed a synthetic tool box for functionalizing polysaccharides (hyaluronic acid, alginate, dextran, pullulan, glycogen, lentinan and carboxymethyl cellulose) with “clickable” aldehydo and hydrazido groups. They allow in vivo hydrogel formation upon mixing. Furthermore, functionalization of clickable polysaccharide strands with bioactive ligands such as cyclic RGD pentapeptides as cell adhesion factors has been achieved in an orthogonal manner. In that way libraries of polysaccharide-based hydrogels were created including those that are based on different polysaccharide backbones.

These studies are complemented with studies on their biophysical properties, biocompatibility and biodegradability as well as substitutes for extracellular matrices.

b) Nanoparticle-drug conjugates

In close collaboration with the group of Michael Ott we designed novel drug-nanoparticle conjugates based on the toxin ansamitocin and iron oxide nanoparticles. The therapeutic effect is initiated by controlled release of ansamitocin from the nanoparticle and by hyperthermia. After injection an external electromagnetic field serves as a release trigger. As major physicotechnical issues energy density as well as the frequency of the electromagnetic field were encountered and solved by redesigning the inductor coil combined with a stronger HF-generator. The efficacy of heating and drug release was improved for use in in vivo studies. The linker architecture between the nanoparticle and the toxin turned out to be a chemical challenge.